From owner-wx-tropl@LISTSERV.ILLINOIS.EDU Fri Oct 22 22:30:28 2010 Received: from vacuum.cso.uiuc.edu (vacuum.cso.uiuc.edu [128.174.5.113]) by cozumel.ust.hk (8.13.8/8.13.8) with ESMTP id o9MEURSm030809 for ; Fri, 22 Oct 2010 22:30:28 +0800 Received: from vacuum.cso.uiuc.edu (vacuum.cso.uiuc.edu [128.174.5.113]) by vacuum.cso.uiuc.edu (8.14.2/8.14.2) with ESMTP id o9LJQBtj014749; Fri, 22 Oct 2010 09:30:14 -0500 (CDT) Received: by LISTSERV.ILLINOIS.EDU (LISTSERV-TCP/IP release 14.5) with spool id 3996433 for WX-TROPL@LISTSERV.ILLINOIS.EDU; Fri, 22 Oct 2010 09:30:14 -0500 Received: from relay07.cites.uiuc.edu (relay07.cites.uiuc.edu [128.174.4.73]) by vacuum.cso.uiuc.edu (8.14.2/8.14.2) with ESMTP id o9MEUDEW009023 for ; Fri, 22 Oct 2010 09:30:13 -0500 (CDT) Received: from weather3.admin.niu.edu (weather3.admin.niu.edu [131.156.8.48]) by relay07.cites.uiuc.edu (8.14.4/8.14.2) with ESMTP id o9MEU6PS018845 for ; Fri, 22 Oct 2010 09:30:13 -0500 (CDT) Received: by weather3.admin.niu.edu (Postfix, from userid 501) id EDC25108B0002; Fri, 22 Oct 2010 09:30:05 -0500 (CDT) X-Proofpoint-Spam-Reason: safe Message-ID: <20101022143005.EDC25108B0002@weather3.admin.niu.edu> Date: Fri, 22 Oct 2010 09:30:05 -0500 Reply-To: wxmaster@COX.NET Sender: WX-TROPL Tropical Storm and Hurricane WX products From: SIU Weather Processor Subject: Pacific-NW: Subj/prognostic Reasoning For Tropical Depression 17w (seventeen) To: WX-TROPL@LISTSERV.ILLINOIS.EDU Precedence: list WDPN33 PGTW 220300 MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC// SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 17W (SEVENTEEN) WARNING NR 04// RMKS/ 1. FOR METEOROLOGISTS. 2. 12 HOUR SUMMARY AND ANALYSIS. A. TROPICAL DEPRESSION (TD) 17W (SEVENTEEN), LOCATED APPROXIMATELY 620 NM NORTHEAST OF SAIPAN, HAS TRACKED NORTHWESTWARD AT 10 KNOTS OVER THE PAST SIX HOURS. ANIMATED INFRARED SATELLITE IMAGERY AND A 221136Z TRMM MICROWAVE PASS DEPICT TIGHTLY CURVED LOW LEVEL BANDING WRAPPING INTO THE SYSTEM CENTER WITH A MAJORITY OF THE DEEP CONVECTION BEING SHEARED TO THE SOUTHWEST. THERE IS FAIR CONFIDENCE IN THE CURRENT POSITION BASED ON THE AFOREMENTIONED TRMM PASS. THE CURRENT INTENSITY ESTIMATE OF 30 KNOTS IS CONSISTENT WITH DVORAK ESTIMATES FROM PGTW AND KNES AT 221130Z AS WELL AS A 221132Z ASCAT PASS INDICATING 25 TO 30 KNOT WINDS. UPPER LEVEL ANALYSIS INDICATES TD 17W IS IN A MARGINAL ENVIRONMENT FOR FURTHER DEVELOPMENT, WITH STRONG DIFFLUENCE ALOFT AND MODERATE NORTHEASTERLY VERTICAL WIND SHEAR. TD 15W IS CURRENTLY TRACKING NORTHWESTWARD UNDER THE INFLUENCE OF A LOW TO MID-LEVEL SUBTROPICAL STEERING RIDGE. 3. FORECAST REASONING. A. THERE IS NO SIGNIFICANT CHANGE IN THE FORECAST REASONING SINCE THE PREVIOUS BULLETIN. B. TD 17W IS FORECAST TO BEGIN TURNING POLEWARD WITHIN THE NEXT 12 HOURS AS THE SUBTROPICAL STEERING RIDGE IS WEAKENED BY A TRANSITORY MID-LATITUDE TROUGH. AFTER TAU 12, THE SYSTEM IS EXPECTED TO TRACK NORTHEASTWARD AHEAD OF A DIGGING MID-LEVEL TROUGH AND WEAKEN TO BELOW WARNING CRITERIA BY TAU 36. THE AVAILABLE NUMERICAL MODEL GUIDANCE IS IN GOOD AGREEMENT WITH THE EXCEPTION OF WBAR WHICH LOOPS THE SYSTEM TO THE SOUTH, INDICATIVE OF A WEAK STEERING ENVIRONMENT. THIS FORECAST IS SLIGHTLY NORTH OF CONSENSUS AND FAVORS A SLOWER POLEWARD TURN AHEAD OF THE TROUGH.// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ To unsubscribe from WX-TROPL send e-mail to LISTSERV@LISTSERV.ILLINOIS.EDU with "unsub wx-tropl" in the body of your message. For help with WX-TROPL write to cnovy@cox.net. For more information on tropical weather products, see the NHC Homepage at http://www.nhc.noaa.gov.